Both digital data and analog data is transmitted through data transmission networks, such as circuit-switched telephone networks and packet data transmission networks, for example the Internet. In upper protocol layers, data transmission is accomplished by establishing connections between nodes of the data transmission network. There is a connection setup phase, a data transmission phase and a connection release phase. There can be an actual physical connection or a connection defined by identification parameters representing specific network nodes. A “node access code” (NAC) is an example of an identification parameter.
A connection that is made by assigning identification parameters of network nodes is also called a logical connection or a virtual connection. Where a virtual connection has been established, data can be transmitted at lower protocol layers without requiring a connection setup phase and a connection release phase in these protocol layers.
A network node is an element of the data transmission network that provides switching functions. Three transmission links are generally connected to each network node. Depending on the connection signaling, data arriving on a transmission link is forwarded to a different transmission link defined by the signaling. Examples of network nodes in circuit-switched data transmission networks are switching centers, private branch exchanges and network nodes. A router is an example of a network node in a packet data transmission networks.
Between switching centers in a circuit-switched data transmission network, signaling can be used that conforms to the ISUP (ISDN User Part) signaling protocol. Between the private branch exchanges of a private branch exchange interconnection, signaling can be used that conforms to the QSIG protocol (Q-interface signaling protocol) or a protocol based on QSIG protocol, such as the Cornet NQ protocol of SIEMENS AG. In the Internet, the signaling protocol TCP (Transmission Control Protocol) is used between the terminals.
In the Internet, communicating identification parameters is accomplished by using either broadcast update messages or flooding. In circuit-switched data transmission networks, however, there is no known method for automatically communicating identification parameters that can be used in the connection setup process to identify network nodes. A method is therefore sought for sending identification parameters between nodes of a circuit-switched data transmission network. An apparatus is desired that communicates identification parameters within a circuit-switched data transmission network.